With the development and deployment of wireless networking devices such as laptop computers, personal digital assistant devices, etc. and infrastructures, consumers and businesses are increasingly being able to realize the benefits of true mobile computing, collaboration, and information exchange. No longer are business travelers required to carry an assortment of cables and search endlessly for an available data port simply to connect to a network to retrieve email messages, download files, or exchange information. No longer are companies and home consumers restrained in where they may access their networks by the location of the Ethernet jacks on the wall. Meeting participants and groups of friends may now form their own ad hoc networks without connecting cables between themselves or logging in to some preexisting network. They can log onto the network using a wireless protocol while running on battery power, thereby allowing even greater mobility
However, while the concept of mobile computing on wireless networks is well accepted, the implementation of this concept has taken on many forms. That is, there now exist several different wireless protocol standards that are competing in the marketplace. These standards include 802.11b (also know as Wi-Fi), 802.11a (also know as Wi-Fi5), 802.11g, HomeRF, Bluetooth, Wireless 1394, HiperLAN2, UWB, ZigBee, etc. Each of these different standards has particular advantages and was and is being developed with particular applications and users in mind. One thing in common with these standards is the use of a network interface module, commonly implemented as a network interface card (NIC).
As mobile workers demand greater mobility, both inside the organization and when traveling, the mobile workers are limited by the lifetime of the battery powering the wireless device. The battery life is a major restriction on mobility. The wireless NIC is the third highest consumer of battery power in a laptop. In small form factor devices, the wireless NIC consumes an even larger percentage of battery power than in a laptop. Most of that energy is used for wireless data transmissions to keep the wireless NIC powered on even when the NIC is not engaged in data transmissions. Since the amount of power a battery provides is limited, how to minimize power consumption to extend the operation time of the device powered by the battery is an important issue for these devices.
One method that has been taken to reduce power consumption of the functions the wireless NIC performs is adjusting the period between performing scanning to determine which devices are in the range of the wireless networking device. For example, U.S. application Ser. No. 10/323,043, filed Dec. 18, 2002 and assigned to the assignee of this application teaches setting the time between scans using an exponential function based on the scanning history and scan results of the latest scan. However, while increasing the time between scans conserves power, more methods to conserve battery power are needed.